Options for Improved Phosphorus Cycling and Use in Agriculture at the Field and Regional Scales

Citation

Schneider, K.D., Thiessen Martens, J.R., Zvomuya, F., Reid, D.K., Fraser, T.D., Lynch, D.H., O'Halloran, I.P., Wilson, H.F. (2019). Options for Improved Phosphorus Cycling and Use in Agriculture at the Field and Regional Scales, 48(5), 1247-1264. http://dx.doi.org/10.2134/jeq2019.02.0070

Plain language summary

Phosphorus is an essential element for all forms of life, but it does not have an indefinite supply. As easily extracted reserves of phosphate rock are depleted, there will be increasing pressure to improve the efficiency of phosphorus use, and to increase recycling back to the land. This may be accomplished through breeding plants that can extract phosphorus from the soil more efficiently, or transfer a greater proportion of the phosphorus that is taken up to the harvested parts of the plant. Adjustments to crop rotations or the addition of organic amendments may encourage colonization by mycorrhizae which improve P uptake. Finally, better ways to recycle P from the waste stream back to agricultural land can be developed, so the phosphorus economy is more circular than linear. Struvite is discussed as one possible way to convert P in wastewater into a marketable fertilizer product.

Abstract

© 2019 The Author(s) and Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada.Soil phosphorus (P) cycling in agroecosystems is highly complex, with many chemical, physical, and biological processes affecting the availability of P to plants. Traditionally, P fertilizer recommendations have been made using an insurance-based approach, which has resulted in the accumulation of P in many intensively managed agricultural soils worldwide and contributed to the widespread water quality issue of eutrophication. To mitigate further environmental degradation and because future P fertilizer supplies are threatened due to finite phosphate rock resources and associated geopolitical and quality issues, there is an immediate need to increase P use efficiency (PUE) in agroecosystems. Through cultivar selection and improved cropping system design, contemporary research suggests that sufficient crop yields could be maintained at reduced soil test P (STP) concentrations. In addition, more efficient P cycling at the field scale can be achieved through agroecosystem management that increases soil organic matter and organic P mineralization and optimizes arbuscular mycorrhizal fungi (AMF) symbioses. This review paper provides a perspective on how agriculture has the potential to utilize plant and microbial traits to improve PUE at the field scale and accordingly, maintain crop yields at lower STP concentrations. It also links with the need to tighten the P cycle at the regional scale, including a discussion of P recovery and recycling technologies, with a particular focus on the use of struvite as a recycled P fertilizer. Guidance on directions for future research is provided.